#include <stdio.h>

void A(int *x,int *y)
{
	int z;
	z=*x;
	*x=*y;
	*y=z;
};

int B(int x,int y)
{
	int z;
	z=x;
	x=y;
	y=z;

	return y;
};


void main()
{
	int x=10;
	int y=20;

	printf("x=%d, y=%d\n",x,y);
	A(&x,&y);
	printf("x=%d, y=%d\n",x,y);


}